This invention relates to electrical wiring conduit and more particularly to wiring conduit for automobile wiring harnesses.
In automobiles, the various electrical components of the vehicle are electrically connected to the battery via electrical leads or wires. These leads are usually grouped together to form what is commonly termed a wire harness. In order to protect the wiring harness from cuts and chafing which might occur from contact with sharp edges, sheet metal parts, body panel attachments, etc., the harness is mounted in a housing. One highly satisfactory type of housing is a plastic corrugated tube which is axially slit throughout its length. The corrugated tubes are versatile in that they can be readily bent for installation and the axial slit allows a lead to be routed out from the harness at any location along the tube.
The corrugated tubes such as those disclosed in Nestor, U.S. Pat. No. 4,384,167 and Ghirardi et al, U.S. Pat. No. 3,711,633, incorporated herein by reference, are generally made of stiff plastic material which adequately protects the wiring harness from chafing and cutting but may produce rattles and unacceptable noise in certain applications.
In applications required to be "squeak-free", the wiring harness has been wrapped with tape and housed in a relatively thick foamed tubing. The tubing is slit axially and secured about the wiring harness by wrapping it with tape at spaced intervals. This tubing, however, does not provide substantial protection for the wire harness and is easily damaged. Moreover, the foamed tubing is bulky, being 3/8 inch to 1/2 inch thick, and is somewhat inconvenient to install.
Accordingly, it is an object of the present invention to provide a new and improved conduit for wiring harnesses which reduces or eliminates noise generation and fully protects the wiring harness from cuts and chafing.
A further object of the invention is to provide such a wiring harness conduit which is compact, convenient to install and durable in use.
Other objects will be in part obvious and will be in part pointed out more in detail hereinafter.
Accordingly, it has been found that the foregoing and related objects are attained in a wiring conduit for housing the electrical wires of an automobile wiring harness which includes a tubular inner wall member of resilient plastic material forming a longitudinal wire passageway for housing the electrical wires and an outer covering of flexible sound-deadening foamed material. The inner wall member is corrugated along its longitudinal axis so as to be flexible in directions transverse to the longitudinal axis and an axial slit extends through the outer covering and the inner wall. In a preferred embodiment, the outer covering is a foamed polymer such as cellular polyethylene and is integrally formed with the tubular wall by spraying or extruding techniques.